Apparatus for transforming electric currents.



E. FALKENTHAL.

APPARATUS FDR TRANSFORMING ELECTRIC CURRENTS.

APPLICATION FILED AUG.12,1912. I

Patented May 2, 1916.

Fig. 4

Fig. 3

Fig.2

Wiineses L1. \I I this specification.

PATENT. OFFICE.

ERWIN FALKENTHAL, OF TRIEDENAU, NEAR BERLIN, GERMANY.

APPARATUS FOR TRANSIORMING ELECTRIC CURRCEN'IS.

To all whom it may concern:

' Be it known that I, ERWIN FALKENTI-IAL, an engineer, and sub ect ofthe German Emperor, residing at Friedenau, near Berlin,

Germany, have invented a certain new and useful Improvement in Apparatusfor Transforming Electric Currents, of which the following is a full,clear, concise, and exact description, reference being had to theaccompanying drawing, forming a part of My invention relates to anapparatus for transforming electric currents, and particularly to anapparatus adapted to transform an alternating current into a pulsatingdirect current or for transforming a direct current into an alternatingcurrent. Therefore the apparatus can be used, in the first case, toapply the loading current for a battery from an alternating currentgenerator, whereas in the second case the apparatus can serve, forinstance in telephone systems, to deliver the ringing current from thecentral battery located at the exchange.

The object of my invention is to produce an instrument with a highefficiency performing the transformation of a current of the one kindinto a current of the other kind with a very small loss. For thispurpose the windings serving to conductand to generate the diiferentkinds of currents are coiled, like the windings of the well-knowntransformers, around a common iron core, nearly or entirely closed andmade of sheetmetal. Furthermore the apparatus is so arranged, that thecommon iron core at the same time and with a minimum of energy serves tooperate the contactor switching device of the apparatus, the armatureoperating said device and having poles of the same polarity at its endsbeing arranged in a' stray-flux of the core, so that it is vibratedthrough the fluctuations or reversals of said stray-flux. By thesearrangements it is acco-mplished that the apparatus herein describedwhen transforming an alternating current into a direct current or viceversa has an efficiency which is nearly or entirely the same as the highefficiency of the wellknown apparatus serving to transform analternating current of a low voltage intoan alternating current of ahigh voltage or vice versa.

vention consists in suitable regulating means in combination with thecontactor switch- Specification of Letters Patent.

Patented May 2, 1916.

Application filed August 12, 1912. Serial No. 714,742.

adapted to raise the efiiciency of the apparatus to a high value. Theseregulating means are arranged to damp or suppress irregular andtherefore disadvantageous self-oscillations of the moved parts of theswitching device, so that the wave of the generatedcur-rent becomes amost favorable one.

' Another feature of my invention relates to regulating means by meansof which, when an alternating current is transformed nto a pulsatingdirect-current for the purpose of loading an accumulator, only thoseparts of the waves of the pulsating direct current are delivered the E.M. If. of which is higher thanthe counter-E. M. F. of the battery to beloaded. i i

I will explain my invention more fully by reference to the accompanyingdrawings in which Figure l is a diagrammatical View of my apparatus;Fig. 1 is a fragmentary view of a portion of my apparatus; and Figs. 2to 4: illustratethe changes in wave form of the current produced by myapparatus.

Referring-to Fig. l 0 denotes an iron core made of sheet metal beforewhich a polarized armature a is arranged to be vibrated. The core 0 ispreferably provided with prominent parts, 11 forming the pole pieces of:the apparatus, so that the core 0 is provided with suitable lateralgaps or air spaces j which are so arranged that the ends of the armaturea are lying in the stray-flux of magnetism generated at said I Thearmature a. 1s polarized in such a vantageously are fastened to thesupport 6 l and have the form of screws. In order that the frictionalcontact between the pins 6 and the ends of the spring (i may .be alwaysthe same, the pins and the spring are made advantageously of differentmetals.

The spring d and the support z' may serve A further important feature ofmy inat the same time to conduct the electric current.

The armature a is further provided with a pendant f which at its endcarries contacts g g Opposite to these contacts 9 g are arrangedcontacts it, h-, so that when the pendant f oscillates in the onedirection the contact g, h is closed, whereas when the pendantoscillatesin the other direction the contact 9 k is closed. The contactsif, k are at the ends of springs F, k which are suitably fastened to theframe of the apparatus or to the iron core 0. Each spring k it consistsof a plurality of springs the length of which is advanta geouslydifferent, as shown in Fig. 1. These springs are arranged one above theother in such a manner that when oscillating they aremovedagainst eachother under a certain pressure, whereby a damping of the oscillatingsystem is secured.

'In order to alter the period of oscillation of the spring systems [6,I0 and to make this period of oscillation equal to the period of thealternating current to be transformed, regulating screws W, n areprovided which are adapted to alter the pressure or friction between thedifferent springs of the spring system 7: and 7: The free ends of thelongest springs k, k strike against projections of stops 0 0 which bymeans of regulating screws 1' r can be adjusted in such a way, that thedistance between the contacts [p 7L and thereby the interval betweenclosing the contacts 9 h and 9 k may be altered. Advantageously thespring systems 71: 70 and the regulating screws M, n are fastened tosaid stops 0 0 Around the iron core 0 a secondary winding 8 and twoprimary windings p 79 are coiled. The two primary windings p 72 areconnected at the middle with the terminal i leading to the one pole of asource of direct current B. The free ends of the windings 72 p areconnected with the springs 70 and 70 The terminal t* which leads to theother pole ofthe source of direct current is connected to the pendant fand the contacts 9 g of this pendant.

The secondary winding 8 is preferably, as shown, electrically connectedwith the primary windings whereby in a well known manner a higherefficiency is secured;

The operation of the apparatus when serving to transform an alternatingcurrent into a pulsating current is as follows: An alternating currentdelivered from a generator G over the terminals t. t to the secondary'winding 8 flows through this winding and the primary windings p, p, inse-.

ries. That current having av wave shown by Fig. 2 sets up an alternatingflux in the core 0 and this alternating flux induces in well knownmanner each of the primary .windln'gs 79 72 The alternatingmagnetization of the core a further sets the armature a in oscillationso that in the first.

half of the period or cycleof the alternab ing current the pendant f ofthe armature (6 holds closed, for instance, the contact 9 h whereas inthe second half of the cycle the pendant holds closed the contact 9 bthe switching of the contacts taking place each time when the E. M. F.of the alternating current changes the sign. Owing to the connectionabove mentioned of the primary windings p, p at the terminals t, t", avarying E. M. F. is set up which however never changes sign. Therefore adirect current is obtained which is not perfectly constant, butpulsating and having about the wave shown by Fig. 3. This wave formrepresents the most favorable case of transformation. But as theoscillating parts of the apparatus herebefore known had the tendency tomake irregular oscil lations and as by this reason the switching of thecontacts did not occur in the right moment, the wave of the obtainedpulsating current practically was not so favorable as shown by Fig. 3,but it was distorted or displaced, whereby the efficiency of theapparatus was decreased. By the damping and regulating means describedabove however the operation. of the apparatus is perfected to such adegree that the wave form shown by Fig 3 can be exactly obtained.

If alternating current is to be trans formed in order to loadaccumulators which have a certain counter E. M. F. it is disadvantageousto generate a pulsating current of the wave form shown by Fig. 3, but itis advisable or even necessary, only to use the wave-parts lying abovethe constant counter-E. M. F., as shown by Fig. 4. In order to obtain apulsating current of such a wave-form, it is suthcient to adjust in asuitable extent the stops 0 0 by means of the screws 1' 7.

It is obvious that the described apparatus can be also used fortransforming a con-- stant direct current into an alternating current.

I do not limit myself to the embodiment of the invention hereinspecifically illustrated as many changes'may be made without departingfrom the spirit-of my invention.

Having thus fully described my invention,what I claim as new, and desireto secure by Letters-Patent is its ends and oscillating in the strayflux of said core. contacts at each end of said direct current winding,a contact member connected to said armature. adapted to contact withsaid contacts alternately, direct current con- 1 motions to said contactmember and to the .mid p t of said d rect urrent winding and means fordamping irregular oscillations of the armature and its associated parts.

-2. Apparatus for transforming electric currents comprising an ironcore, prominent parts forming the'pole pieces of the core, an

alternating current winding around the core, a direct current Windingaround the core, an armature with poles of the same polarity at its endsand oscillating in the stray flux of said core dispersed from said polepieces,

contacts at each end of said direct current winding, a contact memberconnected to said armature adapted to contact with said contactsalternately, direct current connections to said contact member and tothe mid pointof said direct current winding, and means for dampingirregular oscillations of the armature and its associated parts.

3. Apparatus for transforming electric currents comprising an iron coreprovided with gaps or air spaces, an alternating current winding aroundthe core, a direct current winding around the core, an armaturev withpoles of the same polarity at its ends 1 and oscillating in the strayflux dispersed from the gaps of the core, contacts at each end of saiddirect current winding, a con tact member connected to said armatureadapted to contact withsaid contacts alternately, direct currentconnections to said nected to said armature adapted to contact with saidcontacts alternately, direct current connections to said contact memberand to the mid point of said direct current winding and damping means inpart attached to the armature and adapted to permanently cotiperatetherewith and in part attached to the frame and adapted to beperiodically, operated by the armature.

5. Apparatus for transforming electric currents comprising an iron core,a winding coiled around said core, another winding on the core, anarmature with poles of the same polarity at its ends oscillating in astray-flux of the core, contacts adapted to be operated by the armature,said contacts consisting each of a plurality of springs lying one abovethe other. v

6. Apparatus for transforming electric currents comprising an iron core,a winding coiled around said core, another winding on the core, anarmature with poles of the same polarity at its ends oscillating in astrayfiux of the core, contacts adapted to be operated by the armature,said contacts consisting each of a plurality of springs of differentlength lying one above the other, and means for regulating the pressurebetween the different springs.

7. Apparatus for transforming electric currents comprising an iron core,a winding coiled around said core, another winding on the core, anarmature with poles of the same polarity at its-ends oscillating in astrayfiux of the core, contact springs adapted to .be operated by thearmature, stops for limiting the movement of said contact springs, meansforregulatmg said stops.

. E. FALKENTHAL. Witnesses? WOLDEMAR HAUPT, HENRY HASPER.

